Hydro-
-gen
Hydrogen
The name hydrogen derives from the Greek roots hydro- meaning "water" and -gen meaning "producer," reflecting its role in forming water when burned. It was first identified in the 18th century as a distinct gas that, unlike others, combined with oxygen to produce water.

Hydrogen

The name hydrogen derives from the Greek roots hydro- meaning "water" and -gen meaning "producer," reflecting its role in forming water when burned. It was first identified in the 18th century as a distinct gas that, unlike others, combined with oxygen to produce water.

Where is Hydrogen Found?

Hydrogen is abundant in the universe but scarce on Earth, as it is locked in compounds or escapes from the upper atmosphere, due to boil-off. It is produced mainly through water-dependent processes like electrolysis and steam reforming, with water also forming as a byproduct in its use.

Hydrogen production and sources

Hydrogen Isotopes

The three main isotopes of hydrogen are protium, the most common form with no neutron; deuterium, which has one neutron and is stable; and tritium, which has two neutrons and is radioactive. In addition to these, there are a few heavier unstable isotopes of hydrogen which exist briefly before decaying.

Protium
Protium is the most abundant form of hydrogen, made up of a single proton and electron with no neutrons. It’s widely used in fuel cells, chemical production (like making ammonia), and as a clean-burning energy carrier in emerging hydrogen fuel technologies.
Protium structure
Deuterium
A stable isotope with one proton and one neutron, found in heavy water and used in nuclear reactors, climate science, medicinal chemistry, etc.

Possesses different properties to hydrogen and its compounds (heavy water), including a slower rate of reaction due to its larger mass.
Deuterium structure
Tritium
A radioactive isotope with one proton and two neutrons, produced in reactors and used as a tracer in biomedical research, and within glow-in-the-dark lighting for emergency and exit signs.

Tritium is found in nature, where it is produced from interactions of cosmic rays with gases in the upper atmosphere.
Tritium structure